The present invention relates to polyazacycloalkanes, tri-, tetra- or penta-azamacrocyclic complexes, a process for the production of substituted or unsubstituted polyazacycloalkanes, grafted either to an organic polymer, or to a silica gel and the use of such grafted polyazacycloalkanes in the elimination of the metal cations present in a liquid, which can be an effluent, and polyazacycloalkane complexes in the separation of dioxygen from air.
At present, the effluents of irradiated nuclear fuel reprocessing plants and technological effluents of nuclear power stations are treated in an industrial evaporation tower, i.e. a plate column in which distillation takes place under reduced pressure. Such a procedure makes it possible to deplete effluents having a low xe2x88x9d concentration, i.e. for the C.E.A. (COMMISSARIAT A L""ENERGIE ATOMIQUE) centre at VALDUC, effluents having a contamination in xe2x88x9d elements below 1.5.107 Bq/m3 and in saline charge below 50 g/l. This gives a concentrate containing virtually all the xe2x88x9d activity and a saline charge of approximately 300 g/l. This concentrate is treated and subsequently conditioned in concrete. This procedure also makes it possible to bring evaporates consisting of 90% of the aqueous phase of the treated effluents to an activity of 300 to 500 Bq/m3, i.e. well below the discharge value permitted at present (1000 Bq/m3). This procedure has hitherto permitted the discharge of these effluents into the environment following monitoring of the toxic, radiological and chemical elements.
However, as from 1994, the new standards imposed with respect to the discharge into the environment of effluents have become much more strict. Thus, for the Valduc C.E.A. centre, any effluent discharge must have a maximum xe2x88x9d contamination of 1 Bq/m3. Therefore, said effluents must be completely purified in order to bring about a xe2x80x9czeroxe2x80x9d discharge into the environment.
The existing evaporation procedure does not make it possible to satisfy the new discharge standard, because it is not possible to eliminate the phenomenon of entraining xe2x88x9d contamination to the vapour. Therefore this procedure is not sufficiently effective and leads to the obtaining of very slightly charged solutions with a radioactive activity between 200 and 300 Bqxe2x88x9d/m3 (below 1000 Bqxe2x88x9d/m3).
It is therefore necessary to develop complexing agents permitting the treatment of evaporates from industrial evaporation towers in order to eliminate the final traces of xe2x88x9d emitting elements. In addition, these complexing agents could also be used for treating effluents upstream of the industrial evaporation tower, so as to be able to optionally replace the latter, whilst still obtaining effluents having activity levels in accordance with the new environmental discharge standards.
The prior art discloses macrocyclic compounds having excellent complexing properties with respect to cations, anions or even neutral molecules. Thus, FR 2 643 370 in the name of Air Liquide describes derivatives of the following general formula: 
in which A, B, C and D can represent xe2x80x94(CH2)xxe2x80x94, x being between 1 and 4 and W, X, Y and Z representing xe2x95x90Nxe2x80x94(CH2)yxe2x80x94COR, y being between 1 and 4 and R representing an OH, NH2 or ORxe2x80x2 group. These derivatives can be used as complexing agents of metallic elements and in complexed form as oxygen traps.
However, these macrocyclic derivatives are generally highly soluble in water. Therefore the use, recovery and regeneration of said derivatives in solution are not very easy. For these reasons, several fixing methods have been developed in order to graft these macrocyclic derivatives to organic or inorganic supports which are not soluble in water. Thus, U.S. Pat. No. 4,943,375 discloses a macrocycle grafted on silica usable in a separation column for trapping a given ion present in a solution of several ions.
French patent application 2 613 718 describes cyclic tetramines grafted on a polymer and usable for the selective extraction and/or dosing of ions of transition metals and heavy metals. However, these grafted macrocycles suffer from the disadvantage of not being selective of a particular type of metals.
In the nuclear sector, European patent application 347 315 describes a process for separating, by means of crown ethers, uranium and plutonium present in an aqueous fuel resulting from the reprocessing of irradiated nuclear fuels. The crown ether can be DCH 18C6, DCH 24C8 or DB 18C6.
There are a priori numerous applications for said modified polymers, such as e.g. the trapping of metallic elements contained in effluents, the purification of organic solvents contaminated by various cations produced in the electronics industry (cf. C. Pong, xe2x80x9cPolymer material for electronic applicationsxe2x80x9d, E. D. Felt, C. W. Wilkin, Eds: ACS Symposium Series 184, American Chemical Society, Washing D.C., 1982, pp 171-183) or the use of silica gels modified by copper complexes in liquid phase chromatography (cf. M. A. Bagnoud, W. Haerdi, J. L. Veuthey, Chromatographia, 1990, 29, (9/10) pp 495-499). A particularly interesting application relates to the selective coordination properties of gaseous molecules (O2, CO2) of a certain number of complexes formed by these macromolecules with CO(II), Fe(II), Mn(II), Cu(II), etc.
During the last decade a novel dioxygen production process has been developed. Using as a basis natural dioxygen transportation systems (hemoglobin, hemocyanin), it is performed in solution. This process essentially uses COII, FeII, and CuII complexes of tetraazamacrocycles, Schiff bases or porphyrins. The latter selectively fix dioxygen from the air and the desorption stage can be performed electrochemically. This process in solution is usually limited by the life of the oxygenated complexes, which are subject to irreversible degradation reactions by acid hydrolysis in order to form inert complexes no longer having an affinity for dioxygen.
However, it has been demonstrated that the grafting of complexes able to coordinate dioxygen on organic or inorganic, solid matrixes would make it possible to cancel out the decomposition process observed in solution, cf. e.g. the article by J. P. Collman et al, J. Am. Chem. Soc., 1973, 95, 2048 or the article by J. H. Fuhrhop et al, J. Macromol. Sci. Chem., 1979, A13, 545. Moreover, a sufficiently low concentration of grafted complexes adequately moves away the metal centres to prevent any formation of binuclear species. The choice of a relatively hydrophobic polymer reduces the water content of the matrix and therefore the hydrolysis of the oxygenated complex.
The invention aims at removing the disadvantages of the prior art.
To this end, the invention relates to polyazacycloalkanes, characterized in that they comply with one of the three following formulas (I), (II) or (III): 
in which n, m, p, q and r, which can be the same or different, are equal to 2 or 3, R1 is a solid support, R2 represents the hydrogen atom or the group (CH2)2xe2x80x94R3, R3 being a functional group chosen from within the group constituted by COOH, CONH2, CH2OH, CN or COOR4, R4 representing an alkyl or benzyl group, or R2 represents the group xe2x80x94(CH2)xe2x80x94R5, R5 representing COOH or PO3R6, R6 representing an alkyl or hydrogen group, with the exclusion (a) of polyazacycloalkanes of formula (II) in which R1 represents a solid support derived from silica and complying with the formula: 
S representing a silica gel, each R2 represents the hydrogen atom and (i) n and p are equal to 2 and m and q are equal to 3 or (ii) n and p are equal to 3 and m and q are equal to 2 and (b) polyazacycloalkanes of formula (II) in which R1 represents a solid support consisting of an organic polymer and each R2 represents the hydrogen atom.
The silica gels S as used in the invention are defined by KIRK-OTHMER, Encyclopedia of Chemical Technology, third edition, vol. 20, pp 773-775.
The document by M. A. Bagnoud et al, xe2x80x9cOuter-sphere ligand-exchange chromatography with copper loaded macrocyclic-bonded silica columnxe2x80x9d, Chromatographia, 1990, 29, 9/10, pp 495-499 discloses the excluded compound (a), whilst document FR-A-2 613 718 discloses the excluded compound (b).
The solid support can be a crosslinked or non-crosslinked, organic polymer and in particular a radical of a crosslinked or non-crosslinked, organic polymer having an alkyl halide or alkyl chloride termination, such as a radical of a chloromethylated polystyrene of formula: 
or can be a derivative of silica complying with the formula: 
or the formula: 
S representing a silica gel, b being between 1 and 4 and preferably equal to 3 and R7 being an alkyl group or a hydrogen atom.
The term crosslinked or non-crosslinked, organic polymer with an alkyl halide termination means a polymer, whose halogen or halogens have been totally or partly substituted.
Preferably, the grain size of the chloromethylated polystyrene and that of the solid support derived from silica are between 20 and 400 mesh, and preferably between 20 and 70 mesh. This is the grain size of the chloromethylated polystyrene and not that of the radical, which can differ.
When all the nitrogen atoms of the different macrocycles are substituted by propionate groups, these macrocycles have remarkable properties of complexing metals of the lanthanide and actinide series and in particular the europium and gadolinium series. An X-ray analysis shows that the coordination of the metal atom with the macrocycle is performed by oxygen atoms of the carboxylate groups, whereas close macrocycles e.g. described in the article by Spirlet et al, Inorg. Chem. 1984, pp 359-363 or in the article by Dubost et al, C.R. Acad. Sci., Paris Ser. 2, 1991, 312, pp 349-354 have the metal atom coordinated both with nitrogen and oxygen atoms. This result is due to the nature of the groups carried on the nitrogen atoms of the macrocycles according to the invention. As R1 is a solid support, the macrocycles can be used in effluent treatment processes using extraction columns.
Thus, when the solid support is a silica gel, the product obtained has a reduced cost, can easily be regenerated by a simple acid treatment, is stable in most organic solvents and is inert with respect to numerous chemical products. This product can also be used under pressure and in a combustion supporting or oxidizing medium.
When the solid support is of the Merrifield (registered trademark) resin type marketed by Aldrich, the product obtained is physiologically inert and can be used as a selective complexing agent of blood elements, e.g. for the elimination of the cation Cu2+ in a dialysis treatment.
The invention also relates to a process for the production of a substituted polyazacycloalkane grafted on a solid support and consisting of reacting an excess of CH2xe2x95x90CHxe2x80x94R3, R3 being a functional group chosen from among xe2x80x94COOH, xe2x80x94CONH2, xe2x80x94CH2xe2x80x94OH, xe2x80x94CN or xe2x80x94COOR4, R4 being an alkyl or benzyl group, in the presence of a polar solvent such as ethanol, preferably absolute ethanol, with polyazacycloalkane grafted on a solid support R1, complying with one of the following formulas (VII), (VIII) or (IX): 
in which n, m, p, q or r, which can be the same or different, are equal to 2 or 3 and R1 is a solid support on which is grafted the nitrogen atom and chosen from among crosslinked or non-crosslinked, organic polymer, preferably a radical of such a polymer having an alkyl halide termination of the Merrifield (registered trademark) type or a silica derivative complying with one of the two aforementioned formulas, so as to obtain a polyazacycloalkane grafted on a substituted, solid support corresponding respectively to one of the following formulas (X), (XI) and (XII): 
in which n, m, p, q, r, R1 and R3 have the same meanings as hereinbefore.
The invention also relates co the process for grafting an unsubstituted polyazacycloalkane on a solid support of the silica gel type.
According to a first embodiment of the process, reaction takes place in the presence of an aprotic solvent, e.g. such as xylene and under reflux heating: 
S representing a silica gel, R8 being an alkyl group and b being between 1 and 4, preferably equal to 3, with a polyazacycloalkane P, P complying with one of the three following formulas (XIII), (XIV) or (XV): 
in which n, m, p, q and r, which can be the same or different, are equal to 2 or 3, so as to obtain grafted polyazacycloalkanes of formula: 
in which S represents a silica gel and b and P have the same meanings as hereinbefore.
According to a second embodiment of the process, reaction takes place in the presence of an aprotic solvent such as e.g. toluene and under reflux heating: 
with 
S representing a silica gel, R8 being an alkyl group and b being between 1 and 4 and preferably equal to 3, the product obtained then reacting in the presence of water under reflux heating with a polyazacycloalkane P. P complying with one of the following three formulas (XIII), (XIV) or (XV): 
in which n, m, p, q and r, which can be the same or different, are equal to 2 or 3, whilst excluding the case where b=3 and where polyazacycloalkane has the formula (XIV) in which (i) n and p are equal to 2 and m and q are equal to 3 or (ii) n and p are equal to 3 and m and q are equal to 2, so as to obtain the grafted polyazacycloalkane of formula: 
in which S represents a silica gel and P and b have the same meanings as hereinbefore.
The document M. A. Bagnoud, W. Haerdi, J. L. Veuthey, Chromatographia, 1990, 29, 9/10, pp 495-499 already discloses the process for the preparation of grafted polyazacycloalkane corresponding to the exclusion.
The invention also relates to tri-, tetra- or penta-azamacrocyclic complexes of transition metals complying with one of the following formula (IV), (V) or (VI): 
in which n, m, p, q and r, which can be the same or different, are equal to 2 or 3, M is a transition metal chosen from among Ti, Mn, Fe, Co, Ni, Cu. Ru, Rh and Ir, R1 is a solid support of the crosslinked or non-crosslinked, organic polymer type and preferably a radical of such a polymer wich an alkyl halide termination or a silica derivative complying with the formula: 
or the formula: 
S representing a silica gel, b being between 1 and 4 and preferably equal to 3 and R7 being an alkyl group or a hydrogen atom, and R2 represents the hydrogen atom or the group (CH2)2xe2x80x94R3, R3 being a functional group chosen from within the group constituted by COOH, CONH2, CH2OH, CN or COOR4, R4 representing an alkyl or benzyl group or R2 represents (CH2)xe2x80x94R5, R5 representing COOH or PO3R6, R6 representing hydrogen or an alkyl group.
These complexes can be used in processes for the separation or purification of gases, but also during catalytic reactions using gaseous molecules such as O2, CO, CO2 or NO.
Such complexes and more particularly those based on cobalt can also be used in the conditioning of foods, e.g. maintaining an oxygen-free atmosphere.
Finally, the invention relates to the use of a polyazacycloalkane according to the invention for the elimination of the metal cations contained in a liquid such as an effluent or the copper or aluminium contained in a biological fluid such as blood. Such cations are preferably cations of transition metals, heavy metals, metals of group IIIa, lanthanides or actinides and in particular U, Pu, Am, Ce, Eu, Gd, Al, Cr, Mn, Fe, CO, Ni, Cu, Zn, Ag, Cd, Sn, Au, Hg or Pb.
Finally, the invention relates co the use of the aforementioned complexes in the elimination of oxygen from a mixture of gases containing oxygen.